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linux/drivers/rtc/rtc-jz4740.c
Lars-Peter Clausen 7c6a52a090 drivers/rtc/rtc-jz4740.c: fix IRQ error check 
The irq field of the jz4740_irc struct is unsigned.  Yet we assign the
result of platform_get_irq() to it.  platform_get_irq() may return a
negative error code and the code checks for this condition by checking if
'irq' is less than zero.  But since 'irq' is unsigned this test will
always be false.  Fix it by making 'irq' signed.

The issue was found using the following coccinelle semantic patch:

//<smpl>
@@
type T;
unsigned T i;
@@
(
*i < 0
|
*i >= 0
)
//</smpl>

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-06 03:05:03 +09:00

364 lines
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/*
* Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
* Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
* JZ4740 SoC RTC driver
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#define JZ_REG_RTC_CTRL 0x00
#define JZ_REG_RTC_SEC 0x04
#define JZ_REG_RTC_SEC_ALARM 0x08
#define JZ_REG_RTC_REGULATOR 0x0C
#define JZ_REG_RTC_HIBERNATE 0x20
#define JZ_REG_RTC_SCRATCHPAD 0x34
#define JZ_RTC_CTRL_WRDY BIT(7)
#define JZ_RTC_CTRL_1HZ BIT(6)
#define JZ_RTC_CTRL_1HZ_IRQ BIT(5)
#define JZ_RTC_CTRL_AF BIT(4)
#define JZ_RTC_CTRL_AF_IRQ BIT(3)
#define JZ_RTC_CTRL_AE BIT(2)
#define JZ_RTC_CTRL_ENABLE BIT(0)
struct jz4740_rtc {
struct resource *mem;
void __iomem *base;
struct rtc_device *rtc;
int irq;
spinlock_t lock;
};
static inline uint32_t jz4740_rtc_reg_read(struct jz4740_rtc *rtc, size_t reg)
{
return readl(rtc->base + reg);
}
static int jz4740_rtc_wait_write_ready(struct jz4740_rtc *rtc)
{
uint32_t ctrl;
int timeout = 1000;
do {
ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
} while (!(ctrl & JZ_RTC_CTRL_WRDY) && --timeout);
return timeout ? 0 : -EIO;
}
static inline int jz4740_rtc_reg_write(struct jz4740_rtc *rtc, size_t reg,
uint32_t val)
{
int ret;
ret = jz4740_rtc_wait_write_ready(rtc);
if (ret == 0)
writel(val, rtc->base + reg);
return ret;
}
static int jz4740_rtc_ctrl_set_bits(struct jz4740_rtc *rtc, uint32_t mask,
bool set)
{
int ret;
unsigned long flags;
uint32_t ctrl;
spin_lock_irqsave(&rtc->lock, flags);
ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
/* Don't clear interrupt flags by accident */
ctrl |= JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF;
if (set)
ctrl |= mask;
else
ctrl &= ~mask;
ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_CTRL, ctrl);
spin_unlock_irqrestore(&rtc->lock, flags);
return ret;
}
static int jz4740_rtc_read_time(struct device *dev, struct rtc_time *time)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
uint32_t secs, secs2;
int timeout = 5;
/* If the seconds register is read while it is updated, it can contain a
* bogus value. This can be avoided by making sure that two consecutive
* reads have the same value.
*/
secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
while (secs != secs2 && --timeout) {
secs = secs2;
secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
}
if (timeout == 0)
return -EIO;
rtc_time_to_tm(secs, time);
return rtc_valid_tm(time);
}
static int jz4740_rtc_set_mmss(struct device *dev, unsigned long secs)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
return jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, secs);
}
static int jz4740_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
uint32_t secs;
uint32_t ctrl;
secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC_ALARM);
ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
alrm->enabled = !!(ctrl & JZ_RTC_CTRL_AE);
alrm->pending = !!(ctrl & JZ_RTC_CTRL_AF);
rtc_time_to_tm(secs, &alrm->time);
return rtc_valid_tm(&alrm->time);
}
static int jz4740_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
int ret;
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
unsigned long secs;
rtc_tm_to_time(&alrm->time, &secs);
ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC_ALARM, secs);
if (!ret)
ret = jz4740_rtc_ctrl_set_bits(rtc,
JZ_RTC_CTRL_AE | JZ_RTC_CTRL_AF_IRQ, alrm->enabled);
return ret;
}
static int jz4740_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
return jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_AF_IRQ, enable);
}
static struct rtc_class_ops jz4740_rtc_ops = {
.read_time = jz4740_rtc_read_time,
.set_mmss = jz4740_rtc_set_mmss,
.read_alarm = jz4740_rtc_read_alarm,
.set_alarm = jz4740_rtc_set_alarm,
.alarm_irq_enable = jz4740_rtc_alarm_irq_enable,
};
static irqreturn_t jz4740_rtc_irq(int irq, void *data)
{
struct jz4740_rtc *rtc = data;
uint32_t ctrl;
unsigned long events = 0;
ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
if (ctrl & JZ_RTC_CTRL_1HZ)
events |= (RTC_UF | RTC_IRQF);
if (ctrl & JZ_RTC_CTRL_AF)
events |= (RTC_AF | RTC_IRQF);
rtc_update_irq(rtc->rtc, 1, events);
jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF, false);
return IRQ_HANDLED;
}
void jz4740_rtc_poweroff(struct device *dev)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
jz4740_rtc_reg_write(rtc, JZ_REG_RTC_HIBERNATE, 1);
}
EXPORT_SYMBOL_GPL(jz4740_rtc_poweroff);
static int __devinit jz4740_rtc_probe(struct platform_device *pdev)
{
int ret;
struct jz4740_rtc *rtc;
uint32_t scratchpad;
rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
if (!rtc)
return -ENOMEM;
rtc->irq = platform_get_irq(pdev, 0);
if (rtc->irq < 0) {
ret = -ENOENT;
dev_err(&pdev->dev, "Failed to get platform irq\n");
goto err_free;
}
rtc->mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!rtc->mem) {
ret = -ENOENT;
dev_err(&pdev->dev, "Failed to get platform mmio memory\n");
goto err_free;
}
rtc->mem = request_mem_region(rtc->mem->start, resource_size(rtc->mem),
pdev->name);
if (!rtc->mem) {
ret = -EBUSY;
dev_err(&pdev->dev, "Failed to request mmio memory region\n");
goto err_free;
}
rtc->base = ioremap_nocache(rtc->mem->start, resource_size(rtc->mem));
if (!rtc->base) {
ret = -EBUSY;
dev_err(&pdev->dev, "Failed to ioremap mmio memory\n");
goto err_release_mem_region;
}
spin_lock_init(&rtc->lock);
platform_set_drvdata(pdev, rtc);
device_init_wakeup(&pdev->dev, 1);
rtc->rtc = rtc_device_register(pdev->name, &pdev->dev, &jz4740_rtc_ops,
THIS_MODULE);
if (IS_ERR(rtc->rtc)) {
ret = PTR_ERR(rtc->rtc);
dev_err(&pdev->dev, "Failed to register rtc device: %d\n", ret);
goto err_iounmap;
}
ret = request_irq(rtc->irq, jz4740_rtc_irq, 0,
pdev->name, rtc);
if (ret) {
dev_err(&pdev->dev, "Failed to request rtc irq: %d\n", ret);
goto err_unregister_rtc;
}
scratchpad = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SCRATCHPAD);
if (scratchpad != 0x12345678) {
ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SCRATCHPAD, 0x12345678);
ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, 0);
if (ret) {
dev_err(&pdev->dev, "Could not write write to RTC registers\n");
goto err_free_irq;
}
}
return 0;
err_free_irq:
free_irq(rtc->irq, rtc);
err_unregister_rtc:
rtc_device_unregister(rtc->rtc);
err_iounmap:
platform_set_drvdata(pdev, NULL);
iounmap(rtc->base);
err_release_mem_region:
release_mem_region(rtc->mem->start, resource_size(rtc->mem));
err_free:
kfree(rtc);
return ret;
}
static int __devexit jz4740_rtc_remove(struct platform_device *pdev)
{
struct jz4740_rtc *rtc = platform_get_drvdata(pdev);
free_irq(rtc->irq, rtc);
rtc_device_unregister(rtc->rtc);
iounmap(rtc->base);
release_mem_region(rtc->mem->start, resource_size(rtc->mem));
kfree(rtc);
platform_set_drvdata(pdev, NULL);
return 0;
}
#ifdef CONFIG_PM
static int jz4740_rtc_suspend(struct device *dev)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
enable_irq_wake(rtc->irq);
return 0;
}
static int jz4740_rtc_resume(struct device *dev)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
disable_irq_wake(rtc->irq);
return 0;
}
static const struct dev_pm_ops jz4740_pm_ops = {
.suspend = jz4740_rtc_suspend,
.resume = jz4740_rtc_resume,
};
#define JZ4740_RTC_PM_OPS (&jz4740_pm_ops)
#else
#define JZ4740_RTC_PM_OPS NULL
#endif /* CONFIG_PM */
static struct platform_driver jz4740_rtc_driver = {
.probe = jz4740_rtc_probe,
.remove = __devexit_p(jz4740_rtc_remove),
.driver = {
.name = "jz4740-rtc",
.owner = THIS_MODULE,
.pm = JZ4740_RTC_PM_OPS,
},
};
module_platform_driver(jz4740_rtc_driver);
MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("RTC driver for the JZ4740 SoC\n");
MODULE_ALIAS("platform:jz4740-rtc");
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